ASBR法处理苯酚废水的动力学研究

在ASBR反应器中,以苯酚为标的物进行难降解有机物的降解,并研究反应器的降解动力学。经过前期的污泥驯化和正交试验,本试验在ASBR最有效降解污染物的工况下运行。试验结果表明:苯酚初始浓度小于146.8mg/L的情况下,反应速率随苯酚浓度的增大而增大,苯酚的降解过程符合零级动力学反应特征;苯酚初始浓度在200.5～377.9 mg/L之间时,反应速率随苯酚浓度的增大而减小,苯酚的降解过程符合一级动力学反应特征。低浓度和高浓度苯酚在ASBR中降解分别符合零级和一级动力学反应特征,且中温降解速率明显高于常温。本文试验数据与动力学方程拟合较好,能够为实际工艺中的苯酚污水处理提供参考。     

垃圾渗滤液中有机污染物对厌氧氨氧化的影响研究

采用好氧活性污泥和厌氧颗粒污泥混合接种启动UBF厌氧氨氧化反应器,共耗时165d。反应器启动成功后,容积负荷达到了0.17kg总氮/(m3·d),NO2--N与NH4+-N去除率分别为100%和93%。在此基础上进行垃圾渗滤液有机物浓度梯度实验,研究其在不同有机物浓度下对厌氧氨氧化反应的影响作用。实验结果表明:NH4+-N和NO2--N的去除率随有机物浓度的增加依次降低。当TOC浓度小于100mg/L时,厌氧氨氧化运行稳定,NH4+-N和NO2--N的去除率分别达80%和95%以上;当TOC浓度大于200mg/L时,厌氧氨氧化反应减弱,体系中出现了明显的异氧反硝化反应;当TOC浓度大于500mg/L时,厌氧氨氧化反应几乎完全停止。由于该垃圾渗滤液有机污染物多为难降解的大分子,具有毒性、易降解,有机物的含量较少,因此认为其对厌氧氨氧化的毒性抑制远比竞争性抑制大。     

高压静电场提高好氧污泥活性研究

适合强度的高压静电场(HVEF)作用于好氧污泥系统可以提高好氧污泥的活性。通过试验研究发现,在电场强度E=5×10~4V/m,反应器的初始MLSS 1400mg/L,N_s=0.4～0.6kg COD_(Cr)/(kgMLSS·d)的条件下,试验组和对照组都连续运行60个周期的过程中,通过高压静电场效应作用,试验组好氧污泥系统的COD_(Cr)的降解绝对值高于对照组约13～50mg/L,试验组好氧污泥的OUR值较对照组提高了33%～171%。     

低强度超声场促进剩余污泥好氧消化

为了提高剩余污泥好氧消化效率,在消化过程中对剩余污泥进行超声辐射,声强为0.53 W/cm2,频率28 kHz,分别选用0.045 W/mL、0.09 W/mL两个功率密度,每次超声辐射时间20 min或10 min,辐射频次选用4次或2次,组成4个组合.研究表明,未经超声处理的污泥在消化第17天达到稳定,而经超声作用的污泥消化稳定时间较前者提前3～7 d.在相同好氧消化时间内,经超声波处理后污泥能获得更高的有机物降解率.同时对超声波促进污泥好氧消化工艺进行了工程经济评价.     

PTA废水生物处理工艺综述

PTA废水是由对二甲苯(PX)生产PTA过程中产生的排水。废水成分复杂,含大量芳香烃有机物,包括难降解有机物TA和甲基苯甲酸。分析了PTA废水中的芳香烃有机物好氧降解、厌氧降解机理以及TA降解机理。分析结果表明:芳香烃有机物好氧降解速率明显高于厌氧降解速。目前,对于PTA废水处理研究集中在好氧处理和厌氧处理工艺上,重点介绍了PTA废水厌氧、好氧及厌氧-好氧处理的几种工艺及其处理效果。综合投资、能耗、污泥量、操作、处理效率等多种因素,总结出PTA废水处理的最优工艺为厌氧-好氧处理工艺,常用工艺组合包括上旋流厌氧反应器+两级好氧、水解+A/O、两级A/O等。并讨论分析了重金属钴、锰,营养物质N,P,Mg,Fe等以及温度、pH对PTA废水处理效率的影响。同时,展望了PTA废水的研究发展趋势。     

SBR法处理啤酒废水COD与DO的相关关系

介绍了采用SBR法处理啤酒废水时 ,有机物降解过程中COD与DO的相关关系。试验结果表明 ,如改变进水有机物浓度、曝气量或起始混合液污泥浓度 ,在有机物降解过程中DO都有一个缓慢下降的趋势 ,与此同时 ,COD以较大速率被降解。在有机物达到难降解程度后 ,DO迅速大幅度升高 ,标志着反应过程应该结束。此外 ,由于进水COD浓度不同 ,在同一曝气量下DO相差较大 ,可以以初始DO的大小作为预测进水COD浓度的依据 ,调节曝气量 ,控制DO浓度在适宜的范围内。     

气浮—水解酸化—UBF—两段接触氧化工艺处理抗生素废水

某抗生素生产废水污染物浓度很高且对微生物有一定的抑制作用,采用气浮-水解酸化-UBF-两段接触氧化工艺对其进行处理.运行结果表明,当进水CODCr、BOD5、SS分别为12 030 mg/L、3 260 mg/L、2 800 mg/L时,出水相应指标分别为65 mg/L、15 mg/L、46 mg/L,达到<污水综合排放标准>(GB 8978-1996)一级标准.该工艺具有耐冲击负荷能力强、剩余污泥量少、难降解有机物去除率高等优点.     

污水再生利用过程中邻苯二甲酸酯的分布特征

邻苯二甲酸酯(PAEs)是一类重要的环境激素化合物,污水再生过程中难于全部去除PAEs。当含PAEs的再生水用于河道补给时,对于PAEs将发生哪些变化、沉积物对PAEs影响如何等问题的研究较少。因此,选择北京市2座主体工艺为MBR的典型污水再生处理厂,分析其进、出水中6种PAEs组分含量的变化,探讨处理工艺对PAEs去除的机理,研究河道沉积物对PAEs的迁移阻滞作用以及受水前后地下水中PAEs含量变化。结果表明:污水再生处理厂进、出水中检出DMP、DEP、DnOP和DEHP,但DnBP和BBP均低于检出限,进、出水中所检出的组分中DEHP浓度均为最大,分别达到1-10μg/L和0-1μg/L。由于再生水补给河道中的沉积物粒径小、有机质含量在1.0%以上,具有较强的吸附能力,解吸试验显示,沉积物吸附组分包括DMP、DnBP和DEHP,并以DEHP的吸附量最大,达到5.04 mg/kg,其他组分的吸附量在0.01 mg/kg数量级。离河道约100 m的地下水水质检测结果显示,地下水水质已受到再生水中PAEs的影响,检出组分包括DMP和DEHP,浓度分别为42.7 ng/L和1 450 ng/L。     

脱木素-缺氧-好氧生物膜工艺处理造纸废水试验研究

研究了采用脱木素 -缺氧 -好氧生物膜工艺处理造纸废水。其中的脱木素工艺可有效地将黑液中碱木素脱稳析出 ,并提高废水的可生化性。当废水 pH =5 ,绝干纤维污泥与废水COD质量之比为 1 1,硫酸铝投加量为 16 0mg/L时 ,COD去除率大于 6 3%。缺氧水解单元可有效地去除废水中有机污染物质 ,并将难生化降解的高分子有机物转化为低分子有机物。当缺氧水解单元进水COD为 2 2 0 0mg/L,容积负荷为 1 76kgCOD/ (m3·d) ,好氧接触氧化单元容积负荷为 1 11kgBOD/ (m3·d)时 ,出水COD <4 0 0mg/L ,BOD <30mg/L。     

好氧颗粒污泥处理高浓度及难降解废水研究进展

好氧颗粒污泥以其在反应器中污泥沉降速度快、泥水分离简单、污泥浓度高,能够同时实现脱氮除磷等特点成为目前污(废)水处理领域的研究热点之一。对好氧颗粒污泥在高浓度有机废水及难降解废水(硝基苯废水、苯酚废水、氯酚废水、苯胺和氯苯胺废水、含盐废水、染料废水)处理中的研究现状进行综述,重点探讨了好氧颗粒污泥处理该类物质的影响因素、去除机制及其微生物特性等,指出其在难降解废水处理方面具有良好的应用前景。     

Performances of a hybrid adsorption/submerged membrane biological process for toxic waste removal.

This study focuses on a hybrid process, which combines adsorption on powdered activated carbon (PAC), membrane separation using immersed hollow fibers and biological activity. The first part shows that PAC addition in a complex system (containing dissolved molecules and biological particles) can reduce membrane fouling. In that system, DMP removal is function of the activated carbon concentration. Then, respirometric experiments allowed comparison of toxic sensitivity and biological degradation of different bioreactors (membrane bioreactor (MBR), adsorptive membrane bioreactor (PAC-MBR) and classical activated sludge bioreactor (AS)). Results point out that MBR sludge is less sensitive to the toxic than the AS. For high toxic concentration, PAC addition in the MBR decreases rapidly the toxic concentration under the EC50 in the bioreactor, which allows a better biodegradation of the toxic compound. DMP assimilation is completed more rapidly with the PAC-MBR than the MBR.     

IAL-CHS (internal airlift loop--ceramic honeycomb supports) reactor used for biodegradation of 2,4-dichlorophenol and phenol.

The internal airlift loop reactor with ceramic honeycomb supports (IAL-CHS) was applied for biodegradation of 2,4-dichlorophenol (2,4-DCP) and phenol. A strain of DCP-degrading bacteria isolated from activated sludge, Achromobacter sp., was rapidly immobilized onto the ceramic honeycomb supports. The immobilized cells effectively biodegraded 2,4-DCP alone and together with phenol in batch and continuous-flow experiments. For example, 2,4-DCP was biodegraded from an influent concentration of 50 mg/L to less than 1 mg/L with a 6-h hydraulic retention time (HRT) in continuous flow tests. The immobilized biomass grew and accumulated through 2,4-DCP biodegradation, and the rate of degradation increased accordingly.     

Co-degradation of phenol and m-cresols by upflow anaerobic sludge blanket reactor.

The study was performed to assess the efficacy of an upflow anaerobic sludge blanket reactor for the degradation of mixtures of phenol and m-cresol. The experiments were performed in an upflow anaerobic sludge blanket reactor. The reactor was seeded with digested sewage sludge and was initially operated at 24 HRT. A phenol concentration of 200 mg/L was fed to the reactor to acclimatize the microorganisms to phenols. Subsequently the dosages of phenols were increased to 400 mg/L, 500 mg/L, and 600 mg/L. Cresols were introduced in the reactor when phenol removal efficiency of 77% was achieved at phenol concentration of 600 mg/L. Different phenol to m-cresol ratios were tried and the performance of the reactor was evaluated for each case. The result demonstrates that it is important to consider phenol/ m-cresol ratio to avoid toxic effects and both can be co-degraded successfully under anaerobic conditions provided proper acclimatization time is given.     

Fe3+对活性污泥系统的影响

通过小试研究了微量Fe3+对活性污泥系统的影响.将浓度为3 mg/L,5 mg/L,10 mg/L,20 mg/L,30 mg/L,50 mg/L和80 mg/L的Fe3+分别投加到活性污泥系统中,反应4 h后测定系统出水COD、活性污泥的SVI、脱氢酶活性及其EPS组分.结果表明,Fe3+浓度小于50 mg/L时对活性污泥的脱氢酶活性具有促进作用,浓度为10 mg/L时促进作用最强;Fe3+浓度在80 mg/L以下均具有良好的絮凝作用,浓度在30 mg/L以下时絮凝作用最强.两种作用的共同结果影响系统对COD的去除效果.对活性污泥EPS组分的测定表明,Fe3+的絮凝作用对SVI的影响是主要的.     

Photocatalytic degradation of di(2-ethylhexyl)phthalate adsorbed by chitin A.

Di(2-ethylhexyl)phthalate (DEHP) is a ubiquitous environmental contaminant due to its extensive use as a plasticiser and its persistence. Currently, there is no cost-effective treatment method for its removal from industrial wastewater. In a previous study, DEHP was effectively adsorbed from aqueous solution by biosorption onto chitinous materials. Biosorption can pre-concentrate DEHP from the aqueous phase for further treatment. As biosorption cannot degrade DEHP, in this study the degradation (and detoxification) of DEHP adsorbed onto chitinous material by photocatalytic oxidation (PCO) is attempted. PCO relies on hydroxyl radical (.OH), which is a strong oxidising agent, for the oxidative degradation of pollutants. It is a non-selective process which can degrade DEHP adsorbed onto chitinous material. The first part of this study is the optimisation of the degradation of adsorbed DEHP by PCO. Adsorption was carried out in the physicochemical conditions optimised in the previous study, with 500 mg/L chitin A and 40 mg/L DEHP at initial pH 2, 22+/-2 degrees C and 150 rpm agitation for 5 min. After optimisation of PCO, a 61% removal efficiency of 10 mg/L of DEHP was achieved within 45 min under 0.65 mW/cm2 of UV-A with 100 mg/L TiO2, and 10 mM of H2O2 at initial pH 12. The optimisation study showed that UV-A and TiO(2) are essential for the degradation of DEHP by PCO. The degradation intermediates/products were identified by GC-MS analysis. GC-MS results showed that the di(2-ethylhexyl) side chain was first degraded, producing phthalates with shorter side chains. Further reaction produced phathalic anhydride and aliphatic compounds such as alkanol and ester. The toxicities of parental and degradation intermediates in the solution phase and on chitinous materials were followed by the Microtox test. Results indicated that toxicity can be removed after 4 h treatment by PCO. Thus the decontamination of DEHP by integrating biosorption and PCO is feasible.     

Removal of inhibitory phenolic compounds by biological activated carbon coupled membrane bioreactor.

Phenolic compounds cause problems for conventional treatments due to their toxic and inhibitory properties. This work investigated the treatability of phenolic compounds by using two membrane-bioreactor systems, namely: activated sludge coupled with MBR (AS-MBR) and biological granular activated carbon coupled with MBR (BAC-MBR). Initially, the system was fed with phenol (500 mg/L) followed by adding 2,4-dichlorophenol (2,4-DCP). Phenol, 2,4-DCP, TOC and COD removal were higher than 98.99% when the organic load ranged between 1.80 and 5.76 kg/m3.d COD. In addition to MBR system development, removal mechanisms were also investigated. Relatively low values of phenol adsorption of GAC and biomass, and high maximum substrate removal rates obtained from a biokinetic experiment, proved that the removals were mainly due to biodegradation. Analysis of sludge indicated a significant difference in the sludge characteristics of the two reactors. The high EPS content in BAC-MBR led to higher viscosity and poor sludge settling properties. The relationship between sludge properties and EPS components revealed that settleability had no direct correlation with EPS, though it was better correlated to protein/carbohydrate ratios.     

Simulation of DEHP biodegradation and sorption during the anaerobic digestion of secondary sludge.

Di-ethylhexyl phthalate (DEHP) has commonly been found in the sludge of municipal wastewater treatment plants especially during anaerobic processing. It is slowly biodegradable under anaerobic conditions. Due to its high hydrophobicity, sorption-desorption processes can be rate-limiting for the compound biodegradation. In this study, the anaerobic biodegradation of DEHP was investigated through batch kinetic experiments and dynamic transitions of a continuous stirred tank reactor (CSTR) fed with secondary sludge contaminated with DEHP. A widely accepted model (ADM1) was used to fit the anaerobic digestion of secondary sludge and was properly extended to account for DEHP removal, in which mass transfer processes are also involved. It was shown that DEHP removal was limited by the transfer of DEHP within the solid fraction. The criterion selected for the distinction of the two sites was whether the compound sorbed in those sites was bioavailable for biodegradation or not. Thus, the aqueous phase and the surface of the biosolids were considered as suitable sites for the compound to be bioavailable and the main bulk of the solid matrix was regarded as sites, where the compound remains "protected" against biodegradation. The model, fitted to the batch experimental data, was able to predict DEHP removal in the CSTR operated at various HRTs.     

A pilot study on accelerated sludge degradation by a high-concentration membrane bioreactor coupled with sludge pretreatment.

A new sludge treatment process combining a high MLSS membrane bioreactor with sludge pretreatment techniques was studied in pilot-scale experiments. The membrane bioreactor (MBR) was adopted for high efficiency aerobic digestion. The combination of alkaline-ozone treatment of the mixed liquor in the MBR reactor accelerated the biodegradation process by enhancing biodegradability of the sludge. The hydraulic retention time (HRT) of the reactor was set as 3.1 days and the DO level was 1 mg/L on average. After 5 months of operation, the accumulative total solids reduction was more than 70%. Removal efficiency of volatile solids and non-volatile solids were 76% and 54%, respectively. It was found that a considerable portion of the non-volatile solids was dissolved into ions and then flushed out with the effluent. Also, about 41% and 28% of T-N and T-P in the raw sludge were removed although no biological nutrient removal process was adopted. The experiment was run smoothly without significant membrane fouling, even at the relatively high levels of MLSS concentration (11,000-25,000 mg/L). It is concluded that the newly proposed process can significantly increase the sludge reduction efficiency with much shorter retention times.     

杭嘉湖地区饮用水源半挥发性有机物污染现状

采用固相萃取-GC-MS法对杭嘉湖地区16个集中式饮用水源水体中的氯代苯、多环芳烃、硝基苯、多氯联苯、邻苯二甲酸酯等43种半挥发性有机物（SVOCs）进行了分析检测。结果表明,16个集中式饮用水源水共检出10余种有机污染物,浓度范围为0.01~4.26μg/L,检出率为5%~100%;邻苯二甲酸二甲酯、邻苯二甲酸二乙酯、邻苯二甲酸二丁酯、邻苯二甲酸双（2-二乙基己酯）、2,6-二硝基甲苯等化合物的检出率为超过50%;在平水期、丰水期、枯水期,被检出的有机污染物种类分别为12,9,14种,被检出污染物的浓度范围分别为0.05~4.26,0.01~0.20,0.01~1.00μg/L。